Final answer:
A better term for the part of the Moon that is not visible from Earth is the 'far side' of the Moon. The 'dark side' is a misnomer because the Moon experiences day and night just like Earth does. During a new moon, the side of the Moon facing the Sun is not visible from Earth but can be faintly seen due to 'earthshine,' reflected sunlight from Earth's surface.
Step-by-step explanation:
A better term for the part of the Moon we cannot see from Earth is the 'far side' of the Moon, not the 'dark side.' All areas of the Moon experience day and night, just like Earth, due to the lunar rotation. The Moon goes through phases based on its position relative to Earth and the Sun, and at any given time, one hemisphere of the Moon is illuminated by the Sun, while the other is not. The part we cannot see from our vantage point is simply the hemisphere that is turned away from Earth.
During a new moon, the side of the Moon that is illuminated by the Sun is facing away from Earth. At this time, we cannot see the Moon because the sunlight is shining on the side that is not visible to us. However, 'earthshine'—the Sun's light reflected off Earth’s surface—can cause the unlit portion of the Moon to glow faintly, a phenomenon also known as 'the new Moon in the old Moon's arms.'
It's important to note that observations with binoculars or telescopes reveal that the lunar surface brightness varies with its phases, but it is never too bright to observe safely. The earthlight on the Moon is drastically brighter than the moonlight on Earth. Due to Earth's higher albedo, caused by the atmosphere and clouds, Earth reflects much more sunlight than the Moon does.